OBJECTIVE To determine the effect of agents which perturb the cytoskeleton of the trabecular meshwork so as to increase aqueous outflow on contraction of the ciliary muscle in vitro RESULTS H-7 and inhibits actin-based contraction in monkey ciliary muscle DISCUSSION Ciliary muscle strips isolated from the globes of rhesus monkeys which were being euthanized were mounted in a contraction chamber. After equilibration, 105M pilocapine hydrochloride, a just maximal dose for inducing contraction, was perfused throughout the chamber for 15 min. Successively higher concentrations of H-7, an agent which disrupts actomyosin contractility, were then added to the pilocapine bath. The change in force from resting tension was compared to that with pilocarpine alone. FUTURE DIRECTIONS Further characterization of the mechanism of action of H-7 and other cytoskeletally active compounds on anterior ocular segment functions will facilitate their development as antiglaucoma agents. KEY WORDS glaucoma therapy, pilocarpine, actomyosin FUNDING NEI EY02698 PUBLICATIONS Tian B, Millar C, Kaufman PL, Bershadsky A, Becker E, Geiger B H-7 effects on the iris and ciliary muscle in monkeys. Arch Ophthalmol. 116 1070-1077, 1998. [J]